Silverlight piechart Drilldown issue

In my Silverlight app, we show the department level first. we show the budget amount, spending, %, etc. http://img824.imageshack.us/img824/1838/deptview.png then the categories http://img823.imageshack.us/img823/7107/catsview.png and then the items where the problem is: http://img227.imageshack.us/img227/7177/itemsview.png
as you can see at the items. the budget is displaying next to the item however, it used to be the spending there ( the spending column used to be first), I am having trouble to inflict the spending on the item level there because the natural drill down flow is to keep that order. Here is the piechart code I beleive the resolution would be inthere, you can see the order of the colums - how do I get the spending col on the items display. http://pastebin.com/Jb6VHTF9